Pump System and Method for Operating a Pump System

ABSTRACT

The invention is based on pump system ( 10 ), in particular a self-suction pump system, with a liquid conveying unit ( 12 ) for conveying a liquid ( 56 ) and with a vacuum pump unit ( 14 ) which is, at least in an initial operation state, configured to supply the liquid conveying unit ( 12 ) with the liquid ( 56 ). 
     In order to improve a construction, it is proposed that at least in the initial operation state, the vacuum pump unit ( 14 ) is configured to transport a gas along the liquid conveying unit ( 12 ).

The invention concerns a pump system, in particular a self-suction pump system, according to the preamble of claim 1, and a method for operating a pump system according to the preamble of claim 13.

From AU2004237829B2 a pump system with a vacuum pump and a liquid pump is already known, wherein the vacuum pump is operated in dry run and the liquid pump is operated in wet run and, in an initial operation state, the vacuum pump fills a reservoir with a liquid via negative pressure, wherein the reservoir is fluidically connected to the liquid conveying unit and the liquid flows out of the reservoir to the liquid conveying unit due to gravity.

The objective of the invention is in particular, but not limited to, further developing a generic device in an advantageous manner. The objective is achieved according to the invention by the features of claims 1 and 13 while advantageous implementations and further developments of the invention may be gathered from the subclaims.

The invention is based on a pump system, in particular a self-suction pump system, with a liquid conveying unit for conveying a liquid and with a vacuum pump unit which is, at least in an initial operation state, configured to supply the liquid conveying unit with the liquid.

It is proposed that, at least in the initial operation state, the vacuum pump unit is configured to transport a gas along the liquid conveying unit.

Such an implementation allows advantageous further development of a pump system. In particular, a compact construction of the pump system is obtainable. It is advantageously possible to dispense with additional reservoirs which are fluidically connected to the liquid conveying unit. Especially advantageously, the liquid conveying unit and the vacuum pump may be arranged in direct succession, which results in increased construction space efficiency.

By a “pump system” is a system to be understood which is configured to transport at least a liquid along a conduit system. Advantageously the pump system comprises at least one inlet and/or at least one outlet for the liquid, which especially advantageously correspond to a feed conduit and/or an output conduit of the conduit system. For example, the inlet and/or the outlet may comprise a flange, via which the inlet and/or the outlet are/is connectable to the influx conduit and/or the efflux conduit. Alternatively, the inlet and/or the outlet could be connectable to the influx conduit and/or the efflux conduit via a form-fit connection. It would moreover be conceivable that the pump system is firmly integrated in the conduit system. Alternatively, the pump system could also be configured to pump the liquid into a reservoir which could, for example, serve for a transport of the liquid or could be realized as a standing water body. The pump system preferably serves for a transport of residue water and/or wastewater and/or drain water and/or foreign water and/or rain water and/or slack water, and is preferably used with drainages, e. g. for the maintenance of installations comprising liquid-filled tanks or in the case of floods.

By a “liquid conveying unit” is a unit to be understood which is configured to transport a liquid, for example by displacement and preferably by flux-mechanical processes. The liquid conveying unit could, for example, comprise at least one piston element for conveying the liquid. Preferentially the liquid conveying unit comprises at least one liquid conveying rotor. By a “liquid conveying rotor” is an element to be understood which, at least in the continuous operation state, goes through a rotary movement, thus providing the conveying of the liquid. The liquid conveying rotor may in particular be implemented as any customary type of impeller, for example as an axial or semi-axial or radial impeller. The liquid conveying rotor could furthermore have a planar shape or a curved shape; preferentially the liquid conveying rotor has a spiral shape. Preferentially the liquid conveying unit comprises at least one radial pump, in particular a centrifugal pump.

By a “vacuum pump unit” is a unit to be understood which is configured to transport a gas and/or to generate a negative pressure. Advantageously the vacuum pump unit comprises at least one gas inlet, through which the gas flows into the vacuum pump unit at least in the initial operation state, and at least one gas outlet, through which the gas flows out of the vacuum pump unit at least in the initial operation state. The gas could, for example, comprise a waste gas escaping from the liquid and/or air, in particular ambient air. For example, the vacuum pump unit could comprise at least one piston element and/or stator element for a transport of the gas. Preferentially the vacuum pump unit comprises at least one gas conveying rotor. By a “gas conveying rotor” is an element to be understood which, at least in the initial operation state, goes through a rotary movement, thus providing the transport of the gas. Particularly preferentially the vacuum pump unit comprises at least one screw pump with a single screw, of the type used, for example, with vacuum toilets, wherein especially preferentially the gas conveying rotor implements the screw of the screw pump.

It would be conceivable that the vacuum pump unit requires a work pressure that is below the atmospheric pressure; the vacuum pump unit could, for example, comprise a molecular pump. Preferentially, the vacuum pump unit is operable under atmospheric pressure. The vacuum pump could possibly comprise a work space that is sealed off by oil and/or by PTFE and/or by an elastic membrane. For example, the vacuum pump unit could comprise a rotary vane pump and/or a rotary piston pump and/or a scroll pump and/or a piston pump and/or a diaphragm pump. It would also be conceivable that the vacuum pump unit is operable only in dry run. Preferably the vacuum pump unit is operable in dry run as well as in wet run.

By an “initial operation state” is an operation state to be understood in which, due to lack of liquid that is to be conveyed, a liquid pump effect of the liquid conveying unit is considerably reduced in comparison to a continuous operation state, in particular by at least 10%, preferably by at least 20% and particularly preferentially by at least 50%. Preferably, in the initial operation state, the vacuum pump unit transports the gas along the liquid conveying unit in order to induce subsequent flow of the liquid along the liquid conveying unit, in particular such that the liquid conveying unit is completely surrounded by the liquid. Advantageously, the liquid conveying unit is surrounded by the liquid at the end of the initial operation state, as a result of which the pump system changes into the continuous operation state, in which liquid is conveyed continuously. “Configured” is to mean specifically designed and/or equipped. By an object being configured for a certain function is to be understood that the object fulfills and/or executes said certain function in at least one application state and/or operation state.

It is further proposed that the pump system comprises a housing unit, in which the liquid conveying unit is arranged so as to be spaced apart by a gap, wherein the vacuum pump unit conveys the gas through the gap, at least in the initial operation state. Advantageously the vacuum pump unit is also arranged in the housing unit, especially advantageously the gap is arranged between the liquid conveying unit and the vacuum pump unit. Preferably the housing unit comprises a first receiving space, in which the liquid conveying unit is arranged at least to a large extent, and a second receiving space, in which the vacuum pump unit is arranged at least to a large extent, wherein particularly preferentially the receiving spaces are separated from each other by the gap. Alternatively, the vacuum pump unit could be arranged in a further housing unit which is, for example, connected to the housing unit via the gap. Preferentially the gap is part of the gas inlet. This allows achieving a simple construction of the vacuum pump unit. It is advantageously possible to dispense with additional components for manufacturing the gas inlet.

It would be possible that the pump system comprises two separate drive units, which in particular in each case have their own drive housing units, wherein at least in the initial operation state, a first drive unit drives the liquid conveying unit and a second drive unit drives the vacuum pump unit, or that in the initial operation state a drive unit of the pump system drives exclusively the vacuum pump unit. For further simplifying a construction of the pump system, it is proposed that the pump system comprises a drive unit which, at least in the initial operation state, drives the liquid conveying unit and the vacuum pump unit, in particular simultaneously. Advantageously the drive unit comprises exactly one drive housing unit, within which at least one drive member for driving the liquid conveying unit and/or the vacuum pump unit is arranged at least partly. The drive member could, for example, comprise a piston element. It would be possible that the drive unit comprises a combustion engine, preferably the drive unit comprises an electromotor. Theoretically the drive unit could comprise at least one linear motor. In this way a compact implementation of the drive unit is enabled.

It would be conceivable that, in a continuous operation state that follows the initial operation state, the drive unit drives exclusively the liquid conveying unit. For an especially advantageous simplification of a construction of the pump system, it is proposed that in a continuous operation state that, in particular without interruptions like switching off and/or switching on of the drive unit, follows the initial operation state, the drive unit drives the liquid conveying unit and the vacuum pump unit, in particular simultaneously. Preferably the continuous operation state is configured exclusively for a conveying of the liquid. It would be conceivable that an initial operation of the liquid conveying unit and/or of the vacuum pump unit in the initial operation state differs from a continuous operation of the liquid conveying unit and/or the vacuum pump unit in the continuous operation state, for example by a drive power provided by the drive unit or by a drive member used by the drive unit. Particularly preferentially, the initial operation and the continuous operation are identical to each other, in particular the initial operation and the continuous operation differ only by a position of the gas and of the liquid relative to the liquid conveying unit. This allows dispensing with additional components of the drive unit for a switching between different operation modes.

It is moreover proposed that the drive unit comprises a drive shaft, which is configured for driving the liquid conveying unit and the vacuum pump unit. It would be possible that the drive unit comprises a further drive shaft, which is configured at least for driving the vacuum pump unit; the vacuum pump unit could in particular comprise at least one spindle screw pump. Preferentially the drive unit comprises exactly one drive shaft. This allows further simplifying a construction of the drive unit. Advantageously a number of drive members of the drive unit can be reduced.

It would be possible that the liquid conveying unit and/or the vacuum pump unit are/is operatively connected indirectly to the drive shaft, for example via at least one transmission, alternatively the liquid conveying unit and/or the vacuum pump unit could be implemented as stators corresponding to the drive shaft. For further simplifying a construction of the pump system, it is proposed that the liquid conveying unit and the vacuum pump unit are operatively connected to the drive shaft directly. By the liquid conveying unit and the vacuum pump unit being connected operatively to the drive shaft “directly” is to be understood that the drive unit is free of components which are arranged between the drive shaft and the liquid conveying unit, respectively the vacuum pump unit, and which change a rotary movement transmitted from the drive shaft to at least one component of the liquid conveying unit and/or of the vacuum pump unit, for example by changing a rotation direction and/or by changing an angular velocity. It would be possible that the drive unit comprises additional components which are arranged between the drive shaft and the liquid conveying unit, respectively the vacuum pump unit, and which are free of influences on the rotary movement; the drive unit could, for example, comprise at least one hub for mounting the liquid conveying unit and/or the vacuum pump unit to the drive shaft. Furthermore, the liquid conveying unit and/or the vacuum pump unit could be implemented at least partly integrally with the drive shaft. By two components being implemented “partly integrally” is to be understood that the components comprise at least one common element, in particular at least two, advantageously at least three common elements, which is/are constituent/s, in particular functionally relevant constituent/s, of both components. This allows dispensing with additional components of the drive unit for coupling the liquid conveying unit and/or the vacuum pump unit to the drive shaft, like for example transmissions and/or gears.

The liquid conveying rotor is in particular operatively connected to the drive shaft directly. It would be conceivable that the liquid conveying rotor is implemented integrally with the drive shaft, for example as a helix-shaped elevation of the drive shaft. Preferentially the liquid conveying rotor comprises a hub, via which the liquid conveying rotor is mounted to the drive shaft, preferably on an end of the drive shaft. Advantageously, the gap is arranged between the hub and the housing unit. In this way a drive of the liquid conveying unit by the drive shaft is achievable in a simple manner.

The gas conveying rotor is in particular operatively connected to the drive shaft directly. It would be conceivable that the gas conveying rotor comprises a hub, via which the gas conveying rotor is mounted to the drive shaft. Preferentially the gas conveying rotor is implemented integrally with the drive shaft. The gas conveying rotor and the drive shaft could, for example, together form a rotary piston of a rotary piston pump; especially preferentially the gas conveying rotor is implemented as a helix-shaped elevation of the drive shaft, the gas conveying rotor and the drive shaft together forming a screw of a screw pump. Preferably the vacuum pump unit comprises at least one pump housing unit, which accommodates the gas conveying rotor and which may in particular be implemented integrally with the housing unit. It would be possible that the pump housing unit is embodied as a stator and, for example, comprises a counter-thread which corresponds to the gas conveying rotor. Preferably the pump housing unit is planar; especially preferentially the pump housing unit comprises a tube, which in particular defines the second receiving space and within which the gas liquid rotor is arranged. Advantageously the drive shaft is arranged eccentrically with respect to the pump housing unit, in particular with respect to the tube. Particularly advantageously a distance of the gas conveying rotor to a first wall of the pump housing unit is greater than a distance of the gas conveying rotor to a second wall of the pump housing unit that is situated opposite the first wall. Preferably the first wall is arranged on an upper side of the pump housing unit and the second wall is arranged on an underside of the pump housing unit. In this way a drive of the vacuum pump unit by the drive shaft is obtainable in a simple manner. As a result, a great suction force of the vacuum pump unit is achievable by the eccentric arrangement of the drive shaft and the gas conveying rotor.

It would be possible that for a sealing of the vacuum pump unit, the vacuum pump unit comprises at least one sealing element which, for example, seals the gap at the start of the continuous operation state. For the purpose of further simplifying a construction of the vacuum pump unit, it is proposed that the vacuum pump unit is self-sealing by means of a liquid, preferably by means of the liquid. The vacuum pump being “self-sealing” by means of a liquid is to mean that the gap is liquid-impermeable and that during operation of the vacuum pump a liquid film is created that seals the gas inlet. The liquid film advantageously consists of liquid which, after the transport of the gas, flows subsequently to the gas. Alternatively or additionally, the liquid film may consist of liquid that is arranged within the vacuum pump unit and is accelerated from the gas conveying rotor to the gas inlet. This allows preventing an encumbrance of the conveying of the liquid by the vacuum pump unit in a simple manner. It is advantageously possible to dispense with additional components for sealing the vacuum pump unit.

Especially advantageously the pump system comprises a non-return valve, which is arranged at a liquid outlet of the liquid conveying unit. Preferentially the non-return valve is sealed toward the liquid conveying unit and is permeable from the liquid conveying unit onwards. Advantageously, the non-return valve is embodied as a non-return ball valve. Alternatively, the non-return valve could be embodied as a different type of a non-return valve, deemed expedient by someone skilled in the art, for example as a non-return flap valve or as a non-return disk valve. Preferably the non-return valve comprises a receiving space, which is arranged away from a conduit for conveying the liquid and which, in an open state of the non-return valve, accommodates a non-return element of the non-return valve, for example a non-return ball. This allows further improving a construction of the pump system. It is advantageously possible to prevent a reflux of the liquid conveyed by the liquid conveying unit.

It would be conceivable that the non-return valve comprises at least one spring element for a pre-loading of a remaining non-return valve, in particular in order to keep the non-return valve closed. For simplifying a construction of the non-return valve, it is proposed that, at least in the initial operation state, the vacuum pump unit provides a negative pressure which keeps the non-return valve closed. Preferably the non-return valve comprises a pass-through which the non-return valve lies upon in a resting state, the negative pressure pressing the non-return element onto the pass-through. This allows dispensing with additional spring elements for a closure of the non-return element, at least in the initial operation state.

It would be conceivable that the gas outlet of the vacuum pump unit leads into a reservoir or into the surroundings. For further improvement of a construction of the vacuum pump unit, it is proposed that a gas outlet of the vacuum pump unit is arranged with respect to a liquid conveying path downstream of the non-return flap. Advantageously, the vacuum pump unit comprises at least one conduit which connects the work space fluidically to the gas outlet. This allows ensuring clean operation of the vacuum pump in a simple manner. It is advantageously possible to reconvey a portion of the liquid escaping through the gas outlet to a remaining liquid.

The invention is furthermore based on a method for operating a pump system, in particular the pump system, with a liquid conveying unit, by which a liquid is conveyed, and with a vacuum pump unit, by which the liquid conveying unit is supplied with the liquid, at least in an initial operation state.

It is proposed that, at least in the initial operation state, a gas is transported along the liquid conveying unit by the vacuum pump unit. In this way a compact construction of the pump system is obtainable.

The pump system is herein not to be limited to the application and implementation described above. In particular, in order to fulfill a functionality that is described here, the pump system may comprise a number of individual elements, components and units that differs from a number that is given here.

DRAWINGS

Further advantages will become apparent from the following description of the drawings. in the drawings an exemplary embodiment of the invention is illustrated. The drawings, the description and the claims contain a plurality of features in combination. Someone skilled in the art will purposefully also consider the features separately and will find further expedient combinations.

It is shown in:

FIG. 1 a pump system during an initial operation state,

FIG. 2 the pump system during a continuous operation state, and

FIG. 3 a flow chart of a method for operating the pump system.

DESCRIPTION OF THE EXEMPLARY EMBODIMENT

Of objects which are present multiple times, only one is given a reference numeral.

FIG. 1 shows a schematic illustration of a pump system 10 in an initial operation state. The pump system 10 is implemented as a self-suction pump system. The pump system 10 is utilized in drainages.

The pump system 10 comprises a liquid conveying unit 12. The liquid conveying unit 12 serves for a conveying of a liquid 56. Depending on a field of application, the liquid 56 could be embodied as residue water and/or rain water and/or foreign water and/or slack water.

The pump system 10 comprises a liquid feed conduit 44. The liquid feed conduit 44 connects a remaining pump system fluidically to the liquid 56. The liquid feed conduit 44 is embodied as a flexible tube. Alternatively, the liquid feed conduit 44 could be embodied as a piece of tube. The liquid feed conduit 44 is immerged in a region (not shown) filled with the liquid 56. The region could, for example, be a cellar that must be pumped and/or a liquid tank that must be maintained. It would also be conceivable that the pump system 10 could be free of liquid feed conduits 44 and be connectable to a separate liquid feed conduit. Alternatively or additionally, the liquid feed conduit 44 could be embodied as a reservoir conduit 46. The reservoir conduit 46 also serves for retaining a portion of the liquid 56 after operation of the liquid conveying unit 12 in order to prevent a dry run when re-starting the liquid conveying unit 12.

The pump system 10 comprises a liquid output conduit 48. The liquid output conduit 48 is embodied as a flexible tube. Alternatively, the liquid output conduit 48 could be embodied as a piece of tube. The liquid output conduit 48 connects a remaining pump system to a conduit system (not shown) for a disposal of the conveyed liquid 56. The conduit system could, for example, be part of a sewerage. Alternatively, the liquid output conduit 48 could connect the remaining pump system to a liquid reservoir, for example a standing water body or a disposal tank. Furthermore, the pump system 10 could be free of liquid output conduits 48 and be connectable to a separate liquid output conduit.

The liquid conveying unit 12 defines a liquid conveying path 34 from the liquid feed conduit 44 to the liquid output conduit 48. The liquid conveying unit 12 is embodied as a centrifugal pump. The liquid conveying unit 12 comprises a liquid conveying rotor 24. The liquid conveying rotor 24 has a spiral shape.

The pump system 10 comprises a vacuum pump unit 14. In the initial operation state, the vacuum pump unit 14 serves for supplying the liquid conveying unit 12 with the liquid 56. The vacuum pump unit 14 serves for a transport of a gas along the liquid conveying unit 12. The gas is embodied as air. The vacuum pump unit 14 is embodied as a screw pump. The vacuum pump unit 14 comprises a gas conveying rotor 26. The gas conveying rotor 26 has a helical shape. The vacuum pump unit 14 is implemented as a known type of vacuum pump, of the kind that is in particular used for vacuum toilets.

The vacuum pump unit 14 is self-sealing by means of a liquid, which is preferentially equivalent to the liquid 56. In this context it is conceivable that in the initial operation state a small quantity of the liquid is introduced into the region of the vacuum pump unit 14, for example via a separate filling nozzle (not shown). Furthermore, if the liquid feed conduit 44 is implemented as a reservoir conduit 46, the retained portion of the liquid 56 could provide a continuous sealing of the vacuum pump unit. Alternatively, the vacuum pump unit 14 could as well be realized to be not self-sealing, and a certain leakage of gas could be permitted.

The pump system 10 comprises a housing unit 16. The housing unit 16 accommodates the liquid conveying unit 12. The housing unit 16 accommodates the gas conveying rotor 26. The housing unit 16 defines a liquid inlet 42 of the liquid conveying unit 12. The housing unit 16 defines a liquid outlet 30 of the liquid conveying unit 12. The liquid conveying unit 12 is spaced apart from the housing unit 16 by a gap 18. The gap 18 separates a first receiving space 36 of the housing unit 16, in which the liquid feed unit 44 is arranged, from a second receiving space 38, in which the gas conveying rotor 26 is arranged. The gap 18 realizes a gas inlet of the vacuum pump unit 14.

The pump system 10 comprises a drive unit 20. The drive unit 20 is embodied as an electrical motor. Alternatively, the drive unit 20 could be embodied as a combustion motor. The drive unit 20 could furthermore also comprise a plurality of motors arranged in a common housing. The drive unit 20 drives the liquid conveying unit 12 and the vacuum pump unit 14. The drive unit 20 comprises a drive shaft 22. The drive shaft 22 serves for driving the liquid conveying unit 12 and the vacuum pump unit 14.

The liquid conveying unit 12 and the vacuum pump unit 14 are operatively connected to the drive shaft 22 directly. The liquid conveying rotor 24 is mounted to the drive shaft 22 via a hub 40. The gap 18 is arranged between the hub 40 and the housing unit 16. The liquid conveying rotor 26 is embodied as a helix-shaped elevation of the drive shaft 22.

The pump system 10 comprises a non-return valve 28. The non-return valve 28 is arranged at a liquid outlet 30 of the liquid conveying unit 12. The non-return valve 28 prevents a backflow of the liquid 56 from the liquid output conduit 48. The non-return valve 28 comprises a non-return element 50. The non-return element 50 is embodied as a non-return ball. Alternatively, the non-return element 50 could be embodied as a non-return flap or as a non-return disk. In a resting state, the non-return element 50 lies upon a seat (not shown).

The vacuum pump unit 14 comprises a gas outlet 32. The gas outlet 32 is arranged downstream of the non-return valve 28 with respect to the liquid conveying path 34. The vacuum pump unit 14 comprises a conduit 52. The conduit 52 connects the second receiving space 38 to the gas outlet 32.

In order to bring the pump system 10 into the initial operation state like the one shown in FIG. 1, first the liquid feed conduit 44 is immerged into the region and the liquid output conduit 48 is connected to the conduit system. Then the drive unit 20 is activated. After activation of the drive unit 20, the initial operation state is established.

The following explanations explicitly refer to the initial operation state of the pump system 10. The vacuum pump unit 14 transports the gas along the liquid conveying unit 12 and through the gap 18. A pump effect of the liquid conveying unit 12 is negligible due to lack of liquid 56 to be conveyed. The vacuum pump unit 14 transports the gas along the liquid conveying unit 12 in order to bring about a subsequent flow of the liquid 56 from the liquid feed conduit 44. The gas flows through the gap 18, through the vacuum pump unit 14 and out of the gas outlet 32 into the liquid output conduit 48. The liquid 56 accumulates in the first receiving space 36. The vacuum pump unit 14 provides a negative pressure, which keeps the non-return valve 28 closed. The negative pressure induces a pressing of the non-return element 50 to its seat.

FIG. 2 shows the pump system 10 in a continuous operation state that follows the initial operation state. The continuous operation state follows the initial operation state directly. The following explanations refer explicitly to the continuous operation state of the pump system 10. The drive unit 20 continues to drive the liquid conveying unit 12 and the vacuum pump unit 14. The liquid conveying unit 12 is surrounded by the liquid 56. The liquid conveying unit 12 conveys the liquid 56 from the liquid feed conduit 44 to the liquid output conduit 48. A pump effect of the vacuum pump unit 14 is herein negligible. The gap 18 is to a large extent sealed by the liquid 56. The gap 18 is sealed by the liquid 56. Alternatively or additionally, the gap 18 could be sealed by a further liquid, which may in particular be a portion of the liquid 56, which is arranged within the second receiving space 38 and which is transported toward the gap 18 by the gas conveying rotor 26. Furthermore, in case the liquid feed conduit 44 is embodied as a reservoir conduit 46, the retained portion of the liquid 56 could provide a continuous sealing of the vacuum pump unit 14. The non-return valve 28 is open. The non-return element 50 is pressed into a receiving space 54 of the non-return valve 28 by the flowing liquid 56.

FIG. 3 shows a schematic flow chart of a method for operating the pump system 10. In a first operation step 100 the pump system 10 is in the initial operation state. The first operation step 100 is initiated by switching on the drive unit 20. In the first operation step 100 the gas is transported by the vacuum pump unit 14. In the first operation step 100 the pump effect of the liquid conveying unit 12 is equal to zero. The first operation step 100 finishes with the sealing of the gap 18 by the subsequently flowing liquid 56. In a second operation step 110 the pump system 10 is in the continuous operation state. The second operation step 110 follows the first operation step 100 directly. In the second operation step 110 the liquid conveying unit 12 conveys the liquid 56. In the second operation step 110 the pump effect of the vacuum pump unit 14 is equal to zero.

REFERENCE NUMERALS

-   10 pump system -   12 liquid conveying unit -   14 vacuum pump unit -   16 housing unit -   18 gap -   20 drive unit -   22 drive shaft -   24 liquid conveying rotor -   26 gas conveying rotor -   28 non-return valve -   30 liquid outlet -   32 gas outlet -   34 liquid conveying path -   36 first receiving space -   38 second receiving space -   40 hub -   42 liquid inlet -   44 liquid feed conduit -   46 reservoir conduit -   48 liquid output conduit -   50 non-return element -   52 conduit -   54 receiving space -   56 liquid -   100 first operation step -   110 second operation step 

1. A pump system, in particular a self-suction pump system, with a liquid conveying unit for conveying a liquid and with a vacuum pump unit which is, at least in an initial operation state, configured to supply the liquid conveying unit with the liquid, wherein at least in the initial operation state, the vacuum pump unit is configured to transport a gas along the liquid conveying unit.
 2. The pump system according to claim 1, comprising a housing unit, in which the liquid conveying unit arranged so as to be spaced apart by a gap, wherein the vacuum pump unit conveys the gas through the gap, at least in the initial operation state.
 3. The pump system according to claim 1, comprising a drive unit which, at least in the initial operation state, drives the liquid conveying unit and the vacuum pump unit.
 4. The pump system according to claim 3, wherein in a continuous operation state that follows the initial operation state, the drive unit drives the liquid conveying unit and the vacuum pump unit.
 5. The pump system according to claim 3, wherein the drive unit comprises a drive shaft, which is configured for driving the liquid conveying unit and the vacuum pump unit.
 6. The pump system according to claim 5, wherein the liquid conveying unit and the vacuum pump unit are operatively connected to the drive shaft directly.
 7. The pump system according to claim 1, wherein the liquid conveying unit comprises at least one liquid conveying rotor.
 8. The pump system according to claim 1, wherein the vacuum pump unit comprises at least one gas conveying rotor.
 9. The pump system according to claim 1, wherein the vacuum pump unit self-sealing by means of a liquid.
 10. The pump system according to claim 1, comprising a non-return valve, which is arranged at a liquid outlet of the liquid conveying unit.
 11. The pump system according to claim 10, wherein at least in the initial operation state, the vacuum pump unit provides a negative pressure which keeps the non-return valve closed.
 12. The pump system according to claim 10, wherein a gas outlet of the vacuum pump unit is arranged with respect to a liquid conveying path downstream of the non-return valve.
 13. A method for operating a pump system, in particular a pump system according to claim 1, with a liquid conveying unit, by which a liquid is conveyed, and with a vacuum pump unit, by which the liquid conveying unit is supplied with the liquid, at least in an initial operation state, wherein at least in the initial operation state, a gas is transported along the liquid conveying unit by the vacuum pump unit. 